1. Field of the Invention
This invention relates to flare gas stack for waste combustible gas from industrial processes including oil refineries and more particularly to a purge gas conservation system with provisions for controlling the flow of purge gas in accordance with the prevailing conditions including cutting off the purge gas flow when conditions permit.
2. Description of the Prior Art
It has heretofore been proposed to supply purge gas to a flare stack when waste combustible gas is not flowing to the stack and thereby prevent the occurrence of explosions in the stack.
No satisfactory provisions have heretofore been made by others looking to conservation of purge gas when conditions do not justify the supplying of purge gas.
In my prior application for Letters Patent filed Feb. 17, 1977, Ser. No. 769,709, for Flare Gas Stack with Purge Control provisions are made for start up, steady state or transient purge gas control and for failure of the purge gas supply, and take into account variable wind speed at or near the top of the stack and other conditions with provisions for pilot burner gas supply and ignition, and indication of the prevailing conditions.